Foldable distribution container for conveying perishable foods

ABSTRACT

Conventionally, distribution containers, particularly, corrugated cardboard containers and EPS containers, have been used as containers for conveying perishable foods. These containers are disposed as waste after the containers have been used repeatedly by a few times. The amount of these containers disposed as waste is huge, and it has been necessary to reduce the waste, from the viewpoint of resource protection and environmental protection. Particularly, in the EPS containers, bacteria are easily propagated on the inner walls. Further, in the case of the corrugated cardboard containers, they have not been satisfactory from the viewpoint of heat insulation and cooling of the contents. The present invention provides a foldable distribution container for conveying perishable foods of which a foldable container main body and a lid unit covered on the upper opening of the container main body are manufactured as three-wall structures made of a transparent synthetic resin material and having two air layers.

FIELD OF THE INVENTION

[0001] The present invention relates to a distribution container forconveying perishable foods, and relates, more particularly, to afoldable distribution container for conveying perishable foods that canbe easily folded, that is excellent in cold-temperature retention(insulation and cooling effect), and that can be re-utilized.

DESCRIPTION OF THE RELATED ART

[0002] In the distribution of perishable foods such as livestockproducts like frozen meet and marine products like fresh fish, packagingcontainers having various shapes, functions, performance, and materialsare used for perishable foods at present, from the needs ofcold-temperature retention and protection from shock.

[0003] Among them, corrugated cardboard containers have generally beenused as packaging containers for distributing livestock products. Thisis for the purpose of protecting the frozen contents from externalshocks and for distributing the contents in lots. The cool keeping ofthe contents is achieved through keeping of the contents in cold storageand distribution of the contents by refrigerator car. Usually, thecorrugated cardboard containers once used are not utilized again, asthese containers are easily broken and stained, or as the cost ofmanufacturing these containers is low. The once-used containers aredisposed as waste at the retailer side or the consumer side.

[0004] Further, EPS(expandable polystyrene) containers are generallyused as containers for distributing marine products. The purpose of thisis similar to the above. The cool keeping is achieved by similar meansto the above. In addition, excellent heat insulation performance of EPSis utilized. In many cases, after ice or a cold insulator is insertedinto the container, the contents of fresh fish are accommodated.However, bacteria are easily propagated in micro pores of a porousmaterial composition that is a unique characteristic of EPS. Therefore,usually, the EPS container is utilized repeatedly by two or three timesin many cases. Thereafter, the used EPS container is disposed as wasteat the retail side or the consumer side, like the corrugated cardboardcontainer.

[0005] Containers having various shapes have already been provided asdistribution containers that can be re-utilized, such as, distributioncontainers like return boxes, for example. Usually, in order to improvethe accommodation efficiency of these containers in a truck at the timeof recovering the containers, it is required to reduce the volume ofeach container itself by folding the container. Therefore, because ofthe characteristics of the shapes, used materials, or the foldingmechanism of the containers, these containers cannot satisfy the coldinsulation performance that is required for the perishable foods, unlessan optional insulation part is added to each container. Consequently,the corrugated cardboard containers and EPS containers have beenemployed as distribution containers for the perishable foods up to thepresent.

[0006] The corrugated cardboard containers and EPS containers usevarious kinds of materials and have various kinds of structures anddurability, by reflecting the variety of the contents accommodated inthese containers. Further, usually most of them are distributed in oneway from producers to consumers, or used repeatedly by a few times, andare then disposed as industrial waste or combustible waste. The amountof the used packaging containers that are disposed as waste is huge,judging from the amount of perishable foods that are daily consumed.Therefore, it is necessary to reduce the waste from the viewpoint ofglobal resource protection and environmental protection, and thisrequirement has been enhanced recently. However, because of the varietyin functions and performance required for the packaging containers asdescribed above, standardization and common use of the containers havenot yet been realized. As a result, only the problems have been madeclear.

SUMMARY OF THE INVENTION

[0007] In the light of the above situation, the present applicant hasproposed “a foldable distribution container for conveying perishablefoods, comprising: a container main body formed with an approximatelyrectangular bottom plate for mounting perishable foods thereon, fourside walls having hinge portions hinged to four side edges of saidbottom plate and foldable to said bottom plate, and a holding member forholding the erection of said side wall by reinforcing said hingeportions; and a lid unit for covering an upper opening of said containermain body” under Japanese Patent Application No. 2000-373285 A. Further,the present applicant has proposed particularly “a foldable distributioncontainer for conveying perishable foods, wherein said container mainbody and said lid unit are formed as double-wall structures each havingone-layer air layer inside”. According to these containers, it ispossible to assemble and fold the container main body quickly andsecurely in extremely simple operation. Further, it is possible tosecurely shut out the external air and insulate and keep cool the insideof the container. Furthermore, waste is not produced. Thus, there areexcellent effects in the using aspect, the cooling aspect, and theenvironmental aspect.

[0008] It is an object of the present invention to provide a foldabledistribution container for conveying perishable foods capable ofexhibiting further advanced insulation and cooling effect, by addingfurther improvement to a foldable distribution container for conveyingperishable foods.

[0009] The present invention relates to a foldable distributioncontainer for conveying perishable foods, and it is possible to achievethe above object of the invention by a foldable distribution containerfor conveying perishable foods. Namely, the foldable distributioncontainer comprises: a container main body formed with an approximatelyrectangular bottom plate for mounting perishable foods thereon, fourside walls having hinge portions hinged to four side edges of the bottomplate and foldable to the bottom plate, and a holding member for holdingthe erection of the side wall by reinforcing the hinge portions; and alid unit for covering an upper opening of the container main body,wherein the bottom plate and the four side walls that constitute thecontainer main body, and the lid unit are formed as multi-layer wallstructures having a plurality of air layers inside these structuresrespectively.

[0010] Further, it is possible to achieve the above object of thepresent invention more effectively by a foldable distribution containerfor conveying perishable foods, wherein the structures are three-wallstructures having two air layers respectively.

[0011] It is possible to achieve the above object of the presentinvention more effectively by a foldable distribution container forconveying perishable foods, wherein the bottom plate and the four sidewalls that constitute the container main body, and the lid unit are madeof a synthetic resin material.

[0012] It is possible to achieve the above object of the presentinvention more effectively by a foldable distribution container forconveying perishable foods, wherein the synthetic resin material ispolypropylene.

[0013] Further, it is possible to achieve the above object of thepresent invention more effectively by a foldable distribution containerfor conveying perishable foods, wherein a foldable inner case having aset of folding lids is mounted inside the container main body.

[0014] Further, it is possible to achieve the above object of thepresent invention more effectively by a foldable distribution containerfor conveying perishable foods, wherein the inner case is made of amaterial prepared by having an aluminum-deposited polyester film adheredto foamed polyethylene.

[0015] It is possible to achieve the above object of the presentinvention more effectively by a foldable distribution container forconveying perishable foods, wherein the four side walls foldable to thebottom plate are hinged to the adjacent side walls respectively, withtwo opposite side walls formed with angular hinge portions rising fromboth lower ends of the side walls, and the holding members forreinforcing the hinge portions are sliders.

[0016] Further, it is possible to achieve the above object of thepresent invention more effectively by a foldable distribution containerfor conveying perishable foods, wherein the upper surface of the lidunit is formed with recess portions, and the lower surface of the bottomplate of the container main body is provided with projected bases thatare engaged with the recess portions.

[0017] Further, it is possible to achieve the above object of thepresent invention more effectively by a foldable distribution containerfor conveying perishable foods, wherein the lower surface of the bottomplate is formed in a shape to be engaged with the upper opening of thecontainer main body.

[0018] Still further, it is possible to achieve the above object of thepresent invention more effectively by a foldable distribution containerfor conveying perishable foods, wherein the side wall of the containermain body is provided with an IC card accommodation pocket capable ofaccommodating an IC card.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In the accompanying drawings:

[0020]FIG. 1 is a perspective view of the whole container relating toone embodiment of the present invention;

[0021]FIG. 2 is a perspective view of the container main body accordingto the present invention;

[0022]FIG. 3 is a top plan view of the container main body according tothe present invention;

[0023]FIG. 4 is a side view of the container main body according to thepresent invention;

[0024]FIG. 5 is a bottom plan view of the container main body accordingto the present invention;

[0025]FIG. 6 is a perspective view showing a structure of a hingeportion of the container main body according to the present invention;

[0026]FIGS. 7A and 7B are a side view showing a structure of a sliderportion provided on the container main body and a cross-sectional viewcut along the B-B line;

[0027]FIG. 8 is a cross-sectional view of the container main body cutalong the A-A line of FIG. 1;

[0028]FIG. 9 is a perspective view for explaining the sequence offolding the container main body according to the present invention;

[0029]FIG. 10 is a perspective view for explaining the sequence offolding the container main body according to the present invention;

[0030]FIG. 11 is a perspective view for explaining the sequence offolding the container main body according to the present invention;

[0031]FIG. 12 is a top plan view for explaining the sequence of foldingthe container main body;

[0032]FIG. 13 is a time-temperature change characteristic line-diagramshowing the heat insulation and cooling effect of a container relatingto the present invention;

[0033]FIGS. 14A and 14B are a side view showing another structure of aslider portion provided on the container main body relating to thepresent invention and a cross-sectional view cut along the C-C line;

[0034]FIG. 15 is a top plan view showing a status that a container mainbody having the slider portions are folded flat;

[0035]FIG. 16 is a perspective view showing still another structure of aslider portion provided on the container main body relating to thepresent invention;

[0036]FIG. 17 is a perspective view of a container having an inner caserelating to another embodiment of the present invention; and

[0037]FIG. 18 is a perspective view showing a method of folding theinner case.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Embodiments of a foldable distribution container for conveyingperishable foods relating to the present invention will be explained indetail based on attached drawings.

[0039]FIG. 1 is a perspective view showing the appearance of a foldabledistribution container for conveying perishable foods (hereinafter to bereferred to as a “container C”) relating to a first embodiment of thepresent invention. In the drawing, 1 denotes a container main body foraccommodating perishable foods, and 50 denotes a lid unit covered on anupper opening of the container main body 1.

[0040]FIG. 2 is a perspective view showing an internal structure of thecontainer main body 1, with the lid unit 50 removed. This container mainbody 1 consists of a bottom plate 10 and four side walls 20, 21, 22 and23. In other words, the bottom plate 10 is in approximately arectangular shape. The four side walls 20, 21, 22, and 23 are erectedfrom four side edges. These four side walls 20, 21, 22 and 23 and thebottom plate 10 form the container main body 1 capable of accommodatingperishable foods. In FIG. 2, 30 denotes slider portions to be describedlater, and 43 denotes a grip.

[0041] As shown in a top plan view in FIG. 3, four side edges 11 of thebottom plate 10 are connected with four hinges H10. The four side walls20, 21, 22 and 23 are erected, and can be folded on the upper surface ofthe bottom plate 10 with the respective hinges H10 as creases. The fourside walls 20, 21, 22 and 23 are formed as three-wall structuresconsisting of external walls 20 a, 21 a, 22 a and 23 a, inner walls 20b, 21 b, 22 b and 23 b, and intermediate walls 20 c, 21 c, 22 c and 23c, respectively, as shown in partially sectional views in FIG. 3. Twoair layers S1 and S2 are formed between the walls. External air is shutout by these air layers S1 and S2, and the inside of the container mainbody 1 is insulated and held at low temperature. Ribs 35 for reinforcingthe three walls are provided at some portions of the air layers S1 andS2, and the bottom plate 10 and the lid unit 50 also have similarstructures to those of the side walls 20. These will be explained indetail later with reference to FIG. 8. As a result of experimentsrelating to insulation and cooling effect to be described later, it hasbeen confirmed that it is preferable to set 4 to 12 mm, most preferablya value around 8 mm, as the layer thickness of the air layers S1 and S2respectively, that is, the distance between the inner wall and theintermediate wall and the distance between the intermediate wall and theexternal wall respectively.

[0042] The four side walls 20, 21, 22 and 23 and the bottom plate 10that constitute the container main body 1 are formed with a transparentor translucent synthetic resin, preferably polypropylene. With thisarrangement, it is possible to look through the inside of the containermain body 1 from the outside. Further, the inner wall surface of thecontainer main body 1 is a smooth surface having no micro pores at all.Therefore, it is possible to prevent propagation of bacteria inside thecontainer main body.

[0043] The container main bodies 1 are structured such that they can bestacked together in a vertical direction. In other words, as shown in aside view in FIG. 4, the end portion of the bottom plate 10 supportsapproximately a half of the inside of the lower end portions of the sideplates 22 and 23 of the container main body 1. On the other hand, recessportions 22 c and 23 c are provided inside the upper end portions of theside walls 22 and 23. A short-sided portion of the bottom plate 10provided on the bottom portion of a separate container main body 1 thatis stacked above is engaged with these recess portions 22 c and 23 c. Atthe same time, a long-sided portion of the bottom plate 10 is engagedwith the inner wall surface of the side walls 20 and 21. Thus, aplurality of the container main bodies 1 can be stacked together in avertical direction in a status that the inside of each container mainbody 1 is sealed. When the container main bodies 1 are stacked togetherin this way, the lid unit 50 is covered on only the upper opening of thecontainer main body 1 that is positioned at the top of the stacking. Inthis case, the bottom plate 10 of the container main body 1 placed atthe lowest position supports the whole vertical load.

[0044] Further, the lower surface of the bottom plate 10 of thecontainer main body 1 is provided with triangular bases 12, 13, 14 and15 in projection as shown in the side view in FIG. 4 and in a bottomplan view in FIG. 5. These bases 12, 13, 14 and 15 have a function ofpreventing a collapse or a positional deviation of the containers C whenthey are conveyed in a stacked status, as described later. In addition,the bases 12, 13, 14 and 15 have a function of preventing a collapse ofthe container main bodies 1 when they are stacked together in a foldedstatus, as shown in a top plan view in FIG. 12(or FIG. 15).

[0045] The four side walls 20, 21, 22, and 23 that can be folded on thebottom plate 10 are connected together with hinges H12, H2, H3 and H4 atadjacent end portions respectively, as shown in the top plan view inFIG. 3 and in a partially enlarged perspective view in FIG. 6. FIG. 6shows this status for the side wall 20 and the side wall 23. As shown inthe drawing, one end of the side wall 20 is hinged to the adjacent oneend of the side wall 23 with the hinge H1. Similarly, the other end ofthe side wall 20 is hinged to one end of the side wall 22 with the hingeH2. The other end of the side wall 23 is hinged to one end of the sidewall 21 with the hinge H3. The other end of the side wall 22 is hingedto the other end of the side wall 21 with the hinge H4. These hingeportions are formed thin having strength sufficient enough to easilyfold the side walls 20, 21, 22 and 23. As explained above, the four sidewalls 20, 21, 22 and 23 can be folded based on the hinge connection ofmutually adjacent side walls.

[0046] Of the four side walls 20, 21, 22 and 23, two opposite long-sidedside walls are formed with angular hinge portions H5 and H7, and H6 andH8 that rise from both lower ends of the side walls respectively, asshown in the side view in FIG. 4 and a top plan view in a folded statusin FIG. 12. Along these hinges H5, H6, H7 and H8, the corner portions ofthe container main body 1 are folded on the upper surface of the bottomplate 10, as shown in FIG. 12.

[0047] The slider portions 30 are disposed along the hinges H5, H6, H7and H8 respectively, as shown in side views in FIG. 4 and FIG. 7A, andin the top plan view in FIG. 12. FIG. 7A is the side view of a structureof the slider portion 30 disposed on the hinge H8 of the side wall 21 asa part of the slider portions. FIG. 7B is a view of the surface cutalong the B-B line of FIG. 7A. As shown in the drawings, an upper sheathportion 31 is disposed at a right upper slanted position orthogonal withthe hinge H8, and a lower sheath portion 32 is disposed at a lowerslanted position. A slider 33 is slidably inserted in the upper sheathportion 31 and the lower sheath portion 32 respectively. A recessportion 21 h is formed on the surface portion of the side wall 21 wherethe slider 33 is inserted and slides. The lower end of this slider 33can move between a position L indicated by a solid line of the lowersheath portion 32 and a position U indicated by a dotted line of theupper sheath portion 31. When an operator moves the lower end of theslider 33 to the position L with a knob 33 a, the slider 33 works as abar to the hinge H8. Consequently, the erected status of the side wall21 is held firm. On the other hand, when the lower end is moved to theposition U, the holding of the hinge H8 by the slider 33 is canceled,and the corner portion of the side wall 21 becomes foldable along thehinge H8. FIG. 7 and FIG. 12 show the foldable status.

[0048] Further, on the external surface of the side wall 21, there isprovided an IC card accommodation pocket 40 capable of accommodating anIC card 41 on which various kinds of information is written such as thename of a product like perishable foods accommodated in the containermain body 1 and a product convey destination, as shown in the side viewin FIG. 4. With this arrangement, a relationship between theaccommodated product and the convey destination becomes clear, and itbecomes possible to prevent troubles like an error in the contents and atransportation error, etc. Further, at the outside of the side wall 22and the side wall 23 respectively, there is provided a grip 43 forcarrying the container C, as shown in the perspective view in FIG. 2 andin the side view in FIG. 4.

[0049] The lid unit 50 is covered on the upper opening of the containermain body 1 having the above structure. This lid unit 50 is preparedusing the same material and in the same structure as those of thecontainer main body 1, as shown in the perspective view in FIG. 1 and ina sectional view cut along the A-A line of FIG. 1 in FIG. 8. In otherwords, the lid unit 50 is formed as a three-wall structure consisting ofan external wall 50 a, an inner wall 50 b, and an intermediate wall 50c, each made of a transparent or translucent synthetic resin material ofpolypropylene. Two air layers S1 and S2 are formed between the walls.The reinforcing ribs 35 are provided at some portions of the air layersS1 and S2. External air is shut out by this lid unit 50, and the insideof the container main body 1 is insulated and held at low temperature.Further, as the lid unit 50 is made of the same material as that of thecontainer main body 1, the lid unit 50 is crashed together with thecontainer main body 1, and is utilized again as a raw material, afterthe service life of the distribution container.

[0050] As shown in the cross-sectional view in FIG. 8, the lower surfaceof the external peripheral edge portion of the lid unit 50 is cut in ahook shape, and is formed with a stage portion 53. This stage portion 53is engaged with each upper end of the side walls 20, 21, 22 and 23respectively, and has a function of completely cutting the external air.Further, a recess portion 54 is formed inside the upper surfaceperipheral portion of the lid unit 50. This recess portion 54 isdesigned to be engaged with the external side end portions of thestretched bases 12, 13, 14 and 15 respectively provided on the bottomsurface of the container main body 1. Based on this engagement, it ispossible to prevent a collapse or a positional deviation of thedistribution containers when they are conveyed in a stacked status.

[0051] Next, a method of using the container C having theabove-described structure will be explained. Products like perishablefoods are accommodated inside the container main body 1, and thecontainer C is conveyed in a status that the container main body 1 iscompletely sealed with the lid unit 50, as shown in the perspective viewin FIG. 1 and in the cross-sectional view in FIG. 8. Then, the containermain body 1 after it has been used is folded in a flat shape accordingto the order shown in FIG. 9 to FIG. 12.

[0052] First, as explained with reference to FIG. 7, the lower endportion of each slider 33 provided on the side walls 20 and 21 is slidfrom the lower position L to the upper position U. Based on this, theholding of the hinges H5 and H7, and H6 and H8 formed on the side walls20 and 21 by the sliders 33 is canceled, as shown in FIG. 9. Therefore,the side walls 20 and 21 are gradually folded to the inside, with therespective hinges H5 and H7, and H6 and H8 as creases. Along the work ofthe side walls 20 and 21, the short-sided side walls 22 and 23 that arelinked to these side walls and the hinges H1, H2, H3 and H4 are alsogradually folded to the inside, as shown in FIG. 10 and FIG. 11 insequence. Finally, all the side walls are folded flat on the uppersurface of the bottom plate 10, as shown in FIG. 12. As explained above,the container main body 1 is folded flat in simple operation by onlyslightly sliding the sliders 33.

[0053] On the other hand, in the case of assembling an erected containermain body 1 as shown in FIG. 2 from the folded status as shown in FIG.12, this can be achieved by carrying out the operation in the oppositeorder to that of the folding operation. In other words, the side walls22 and 23 of the container main body 1 in the folded status as shown inFIG. 12 are stretched to the left and right respectively by holding theupper end of the side wall. Then, the side walls 20, 21, 22 and 23 areerected immediately. In this status, the lower end portion of eachslider 33 is slid from the upper position U to the lower position L,thereby to firmly hold the erected status of the side walls 20, 21, 22and 23. As explained above, the container main body 1 according to theembodiment of the present invention can be assembled or folded flat inextremely simple operation.

EXAMPLE

[0054] In order to confirm the heat insulation and the coolingeffect(low-temperature retention) of the container C explained above,the following experiments have been carried out by making trials ofvarious kinds of containers with changed materials that constitute thecontainer C and changed sizes of structures.

[0055] First, three kinds of materials are selected for manufacturingthe container main body 1 and the lid unit 50 respectively. Namely, acontainer C1 is manufactured using a synthetic resin(polypropylene), acontainer C2 is manufactured using corrugated cardboard, and a containerC3 is manufactured using EPS. Next, structures that constitute thecontainer main body 1 and the lid unit 50 are selected as follows. Thecontainer C1 has the following three types. A container C1 a has two airlayers(S1, S2), each having a layer thickness of 8 mm, and the wallsthat form these air layers have a thickness of 2 mm respectively.Similarly, a container C1 b has two air layers(S1, S2), each having alayer thickness of 5 mm, and the walls that form these air layers have athickness of 2 mm respectively. Then, a container C1c relating to theabove-described prior application has one air layer having a layerthickness of 14 mm, and the walls that form this air layer have athickness of 2 mm respectively. Further, the container C2 and thecontainer C3 have no dirt(no air layers) respectively, and walls ofthese containers have a wall thickness of 15 mm and 5 mm respectively.The capacity of 2000 cc is set to each of the above five kinds ofcontainers(that is, C1 a, C1 b, C1 c, C2 and C3).

[0056] Next, 2000 cc of an antifreezing fluid at −15° C. is sealed intothese five kinds of containers that have been manufactured in theabove-described manner. Temperatures of the inside of each containeralong the lapse of time(0 to 8 hours)are measured with a self-recordingthermometer in the room at a normal temperature(22° C.). As a result,data showing temperature changes(a vertical axis) along the lapse oftime(a horizontal axis) as shown in FIG. 13 has been obtained.

[0057] As can be understood from FIG. 13, the temperature within eachcontainer gradually rises along the lapse of time. Containers withexcellent heat insulation and cooling effect, that is, the containers inwhich the rise in temperature is small along the lapse of time, are inthe order of the containers C3, C1 a, C1 b, C1 c and C2. Following thecontainer C3(the EPS container), the container C1 a(the polypropylenecontainer, with an air layer thickness 8 mm) is excellent, and thecontainer C2(the corrugated cardboard container) shows the worst value.However, while the EPS container C3 is excellent from the viewpoint ofthe heat insulation and cooling effect, this container has drawbacks inthat bacteria are easily propagated in micro pores of the inner wall,and that the used container is disposed as waste, as described above. Onthe other hand, the synthetic resin container provided with air layers,particularly, the container C1 a, has heat insulation and coolingeffect, and has no propagation of bacteria, as the inner wall surface issmooth. Further, this container has a high practical value, as thiscontainer can be re-utilized. It is also possible to provide three ormore air layers in the structures. However, this leads to an increase inmanufacturing cost along the complexity of the structures. Furthermore,from the viewpoint of heat insulation and cooling effect, it ispreferable to form the above-described two-layer structures.

[0058] In investigating the synthetic resin(polypropylene) container C1from the viewpoint of heat insulation and cooling effect, it is morepreferable to provide two air layers than to provide one air layer oneach structure. Further, the layer thickness of 8 mm is preferable to 5mm. Further, according the experiments carried out by the presentinventors, it has been found that the practical range of the layerthickness is 4 to 12 mm, and most preferably, 8 mm. This is because theheat insulation and cooling effect becomes lower when the layerthickness is equal to or less than 3 mm. Also, the heat insulation andcooling effect similarly becomes lower when the layer thickness is equalto or larger than 13 mm, because of the generation of convection insidethe air layers.

[0059] While the content of the present invention has been explainedabove with reference to one example, the present invention is notlimited to this example, and it is also possible to make variousmodifications to the construction as follows.

[0060] First, as the holding member for holding the erection of the sidewalls, it is possible to use slider portions 30A as shown in FIGS. 14Aand 14B in stead of the slider portions 30. As shown in a front view inFIG. 14A and in a cross-sectional view cut along the C-C line of FIG.14A in FIG. 14B, slider portion 30A is provided in a vertical directionacross a hinge H8 formed on a side wall 21. It is so structured that aslider 33 is slid along a vertical distance between an upper sheathportion 31A and a lower sheath portion 32A as shown by arrow marks,thereby to erect the side wall 21 and cancel the erection. With theslider portion 30A provided in this way, the floating of the upper endportion of the slider 30A is restricted by the lower surface of thecontainer main body 1 positioned above, that is, by the bottom surfaceof the bottom plate 10, at the time of conveying the container mainbodies 1 in a stacked status. Therefore, it is possible to hold theerection of the side wall 21 securely and firm, during the conveyance.When the container main body 1 provided with this slider portion 30A isfolded flat as shown in FIG. 15, the upper portion of the knob of theslider portion 30A is stretched above from the top of the side wall 20and the side wall 21 respectively. Consequently, the side wall 20 andthe side wall 21 are pressed against the upper surface of the bottomplate 10. As a result, it is possible to fold the whole unit more flat.

[0061] As a further modification of the holding member, it is alsopossible to use sliders 30B as shown in FIG. 16. These sliders 30B areprovided with a U-shaped channel member facing downward respectively,and are slidable on the upper end portions of the side wall 20 that isformed with angular hinges H5 and H7 and the side wall 21 that is formedwith angular hinges H6 and H8 respectively, out of the four side walls20, 21, 22, and 23 of the container main body 1. For erecting the sidewalls 20 and 21, the sliders 30B are disposed on the top of the hingesH5, H6, H7 and H8 respectively, as shown in FIG. 16. For folding thesliders 30B, the sliders 30B are removed. According to these sliders30B, it is possible to manufacture the container at low cost because ofa simple mechanism. However, some device is necessary in the aspect ofsealing between the lid unit 50 and the container main body 1.

[0062] Further, as a method of folding the container main body 1, it ispossible to employ various known methods, such as a method used for aplastic container disclosed in Japanese Patent Application Laid-open No.9-175541 A, for example. According to this method, at the time of vacuummolding a plastic sheet, ribs that can be folded toward the inside, whenthe container after the molding is pressed to the up and downdirections, are integrally formed on side walls. Therefore, this plasticcontainer is suitable for conveyance and storage in a status that theside walls are folded flat.

[0063] The above explains the container C structured in a single unitconsisting of the container main body 1 and the lid unit 50, foraccommodating perishable foods therein. It is possible to furtherincrease the heat insulation and cooling effect of the containeraccording to the present invention, by providing a container C′ that ismounted with an inner case(an inner box) 100 that is foldable inside thecontainer main body 1, as shown in a perspective view in FIG. 17. Thisinner case 100 is a foldable box unit having a set of folding lids thatare prepared by using a material consisting of an EPS sheet of a few mmthickness adhered with a thin aluminum-evaporated polyester film, withthe aluminum-deposited surface facing inside. As shown in the drawing,this container C′ has a set of foldable lid units 150 a and 150 b on thetop. FIG. 18 shows a folded status in a perspective view. The containerC′ has four side walls 120, 121, 122, and 123 around, and has bottomplates 110 a and 110 b at the bottom. This inner case 100 is designed asfollows. When the inner case 100 is developed, this becomes large enoughto be brought into contact with the inner surface of the container mainbody 1 including the lid unit 50 and the bottom plate 10 of thecontainer C, and when the inner case 100 is folded as shown by arrowmarks in FIG. 18, this becomes in a flat plate shape. For the materialof the inner case 100, it is also possible to use various kinds ofplastic films or flexible sheets having heat insulation property, inaddition to the above-described deposited film. However, it ispreferable to use the above-described material from the viewpoint ofheat insulation and cooling effect. Further, it is needless to mentionthat it is possible to employ various kinds of known methods for foldingthe inner case 100.

[0064] For using the container C′ having the inner case 100 accommodatedtherein, perishable foods are accommodated inside the inner case 100,and the lid units 150 a and 150 b are closed. Further, the lid unit 50is covered on the upper opening of the container main body 1, thereby toinsulate the inside in double. In the case of the container C′ that usesthis inner case 100, it is needless to mention that it is not necessaryto manufacture the container main body 1 and the lid unit 50 with atransparent or translucent material.

[0065] As explained above, according to the present container C′, theinside of the container main body 1 is heat-insulated in double.Therefore, it is possible to further improve the heat insulation andcooling effect. Further, according to the experiments carried out by thepresent inventors, it has been made clear that changes in temperature ofthe container C′ along the lapse of time show approximately intermediatevalues between the values of the container C3(the EPS container) and thecontainer C1 a (the polypropylene container having two air layers, withthe layer thickness of 8 mm) shown in FIG. 13.

[0066] As explained above, according to the foldable distributioncontainer for conveying perishable foods relating to the presentinvention, it is possible to obtain the following effects.

[0067] (1) The container main body is formed with an approximatelyrectangular bottom plate for mounting perishable foods thereon, fourside walls having hinge portions hinged to four side edges of the bottomplate and foldable to the bottom plate, and a holding member for holdingthe erection of the side wall by reinforcing the hinge portions.Therefore, it is possible to assemble and fold the container main bodyquickly and securely in extremely simple operation.

[0068] (2) Particularly, the four side walls foldable to the bottomplate are hinged to the adjacent side walls respectively, with twoopposite side walls formed with angular hinge portions rising from bothlower ends of the side walls, and sliders for reinforcing the hingeportions are provided. According to this container, it is possible tofurther improve the above effect.

[0069] (3) Further, the bottom plate and the four side walls that formthe container main body, and the lid unit are formed as three-wallstructures having two air layers inside respectively. Therefore, it ispossible to securely shut out the external air and insulate and keepcool the inside of the container.

[0070] (4) It is possible to further improve the above effect,particularly by providing a container having a foldable inner case, witha set of folding lids mounted inside the lid unit and the container mainbody, more preferably, a container having the inner case made of amaterial prepared by having an aluminum-deposited polyester film adheredto foamed polyethylene

[0071] (5) Further, as the bottom plate and the four side walls thatform the container main body, and the lid unit are made of the samematerial consisting of a transparent synthetic resin, it is possible toconfirm the products accommodated in the container main body from theoutside. Further, as the inner wall of the container main body is asmooth surface having no micro pores at all, it is possible to preventpropagation of bacteria. After using the container main body, it ispossible to use this container main body again by simply cleaning it.Further, as the container main body and the lid unit are made of thesame material, it is possible to use them for recycling of the rawmaterial, by crashing the container after the lapse of the serviceperiod.

[0072] (6) Further, as a recess portion is formed on the upper surfaceof the lid unit, and also stretched bases for engagement with thisrecess portion are provided on the lower surface of the bottom plate ofthe container main body, a collapse or a positional deviation does notoccur even when a plurality of distribution containers are conveyed in astacked status. When the container main bodies are stacked in a flatfolded status, the bases are engaged with the recess portion formed onthe container main body positioned above. Therefore, it is possible toprevent a positional deviation.

[0073] (7) Further, as the lower surface of the bottom plate is formedin a shape to be engaged with the upper opening of the container mainbody, it is possible to seal the inside without the lid unit, bystacking the distribution containers.

[0074] (8) Further, as an IC card accommodation pocket capable ofaccommodating an IC card is provided on the side wall of the containermain body, a relationship between the accommodated product and theconvey destination becomes clear. It also becomes possible to preventtroubles like an error in the contents and a transportation error, etc.

What is claimed is:
 1. A foldable distribution container for conveyingperishable foods, comprising: a container main body formed with anapproximately rectangular bottom plate for mounting perishable foodsthereon, four side walls having hinge portions hinged to four side edgesof said bottom plate and foldable to said bottom plate, and a holdingmember for holding the erection of said side wall by reinforcing saidhinge portions; and a lid unit for covering an upper opening of saidcontainer main body, wherein the bottom plate and the four side wallsthat constitute said container main body, and said lid unit are formedas multi-layer wall structures having a plurality of air layers insidethese structures respectively.
 2. A foldable distribution container forconveying perishable foods according to claim 1, wherein said structuresare three-wall structures having two air layers respectively.
 3. Afoldable distribution container for conveying perishable foods accordingto claim 1 or 2, wherein the bottom plate and the four side walls thatconstitute said container main body, and said lid unit are made of asynthetic resin material.
 4. A foldable distribution container forconveying perishable foods according to claim 3, wherein said syntheticresin material is polypropylene.
 5. A foldable distribution containerfor conveying perishable foods according to any one of claims 1 to 4,wherein a foldable inner case having a set of folding lids is mountedinside said container main body.
 6. A foldable distribution containerfor conveying perishable foods according to claim 5, wherein said innercase is made of a material prepared by having an aluminum-depositedpolyester film adhered to foamed polyethylene.
 7. A foldabledistribution container for conveying perishable foods according to anyone of claims 1 to 6, wherein the four side walls foldable to saidbottom plate are hinged to the adjacent side walls respectively, withtwo opposite side walls formed with angular hinge portions rising fromboth lower ends of said side walls, and said holding members forreinforcing said hinge portions are sliders.
 8. A foldable distributioncontainer for conveying perishable foods according to any one of claims1 to 7, wherein the upper surface of said lid unit is formed with recessportions, and the lower surface of the bottom plate of said containermain body is provided with projected bases that are engaged with saidrecess portions.
 9. A foldable distribution container for conveyingperishable foods according to any one of claims 1 to 8, wherein thelower surface of said bottom plate is formed in a shape to be engagedwith the upper opening of said container main body.
 10. A foldabledistribution container for conveying perishable foods according to anyone of claims 1 to 9, wherein the side wall of said container main bodyis provided with an IC card accommodation pocket capable ofaccommodating an IC card.